Metal detector
An electronic device that senses metal buried in the ground and is used to find iron meteorites and metal-rich stones.
A metal detector sends a changing magnetic field into the ground from a coil and listens for the signal that comes back when it passes over something that conducts electricity. Iron meteorites, which are mostly iron-nickel metal, give a strong signal. Ordinary chondrites, the commonest stony meteorites, contain enough metal flecks to be detected if they are near the surface.
Detectors have found huge numbers of iron meteorites in places where they lie buried, such as the Sikhote-Alin strewn field in eastern Russia, where a shower of iron fell in 1947, and at Campo del Cielo in Argentina. Without them, many pieces hidden in soil would never be recovered.
They are not perfect. Many rare meteorites, such as most carbonaceous chondrites and achondrites, contain little or no metal and may be silent. Meanwhile some Earth rocks rich in magnetite, which detectorists call hot rocks, give false signals, as do nails and scrap. Anyone using a detector must first get the landowner's permission. Metal detecting is banned or controlled on many protected sites and in some countries, so check the rules before you set out, and fill in any holes you dig.
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Level: Explorer Ages 10 and up